Lactic Acid Bacteria As Microbial Cell Factories: Updating the Heterologous Expression Toolbox

Lactic acid bacteria (LAB) are a "generally regarded as safe" microorganisms which are traditionally used in food fermentation and as chassis for heterologous protein production. The order of LAB include mainly Lactobacillus, Leuconostoc, Pediococcus, Lactococcus, and Streptococcus. In recent years, they have also emerged as gut delivery tools and cell factories for protein therapeutics and within food fermentation. However, these applications are heavily depended on the secretion efficiencies and capabilities of LAB. To facilitate rapid and productive heterologous expression, an efficient recombinant protein expression toolbox is required.

In our labs, an entire suite of tools – ranging from promoters, chaperones, tags and solubility partners - have been examined to accelerate the design, build and test process of optimizing recombinant protein expression. In this presentation, we will focus on (1) the comparison of secretion tags and new solubility partners and (2) also describe new propeptide sequences for enhancing solubility and secretion efficiencies in LAB.